There would be chaos. The Daily Prophet would have a field day, with headlines splashed all over. The Order of the Phoenix might be torn apart, some believing in Harry and others condemning him. The pure - blood families who always disliked Harry would use this as an excuse to try and get him expelled from the wizarding world. It would also make the relationship between Gryffindor and Slytherin houses even more strained than before.
The wizarding world would be divided. There would be those who would still believe in Harry's innocence and think there must be some explanation behind his actions. However, a large part would see it as a heinous act. The Ministry of Magic would likely get involved, and Harry might even be hunted down as a criminal. Snape's allies, if he had any, would surely seek revenge.
Most would be in shock. The students at Hogwarts who looked up to Harry would be deeply disappointed and confused. The teachers would be horrified and would immediately start an investigation. Some might even turn against Harry, believing he had finally gone too far.
The reaction would also depend on how the events leading up to these actions were presented in the fanfiction. If it was made clear that Harry was acting in self - defense or to protect the wizarding world from a hidden threat, some might come to his side. But overall, it would create a huge upheaval in the wizarding world. The Ministry of Magic would be under pressure to take action, and there would be a lot of unrest among the students at Hogwarts who looked up to both Snape and Moody in different ways.
Some students at Hogwarts might be disappointed. They could have been secretly enjoying his fanfiction works and were looking forward to new stories.
Some might be angry, thinking he's abandoning his responsibilities. The Ministry of Magic might try to persuade him to come back or even use force if they thought it was necessary for the safety of the wizarding world. His friends, on the other hand, would likely be sad and try to understand his reasons. They might also try to convince him to return, as they know how much he means to the fight against evil in the wizarding world.
Well, there would be a huge uproar. Pure - blood supremacists would likely use this as an example of how the wizarding world was going to the dogs. The Hogwarts faculty would be divided. Those who knew Snape well might suspect there was more to the story, but those who only knew his past would condemn him. Hermione herself would face a great deal of ostracism. She might have to leave her job at the Ministry if the public outcry was too much. And her relationship with her friends could be severely strained as they struggle to come to terms with this unexpected and controversial situation.
They would be devastated. Harry has many friends and allies. People like Hermione and Ron would be heartbroken and would probably seek revenge. The Hogwarts faculty would also be deeply affected. Dumbledore, if he's still alive in the fanfiction, would feel a great sense of guilt for not protecting Harry better. There might be a split in the wizarding community, some believing the Dursleys were acting on their own, others suspecting a darker conspiracy.
There would be a great deal of shock and confusion. Many would start to question everything they had believed in. Families would be divided. Some might think that Harry had been corrupted by Voldemort's dark magic and try to find a way to reverse it. The Ministry of Magic would be in a panic. They would try to come up with new strategies to deal with this new threat. Teachers at Hogwarts would be worried about the safety of their students. And the Death Eaters, while initially happy to have Harry on their side, would also be suspicious of his motives and loyalty.
The wizarding world would likely be in shock. Harry is seen as a symbol of hope against Voldemort. His death at the hands of Vernon would be a huge blow. There would probably be a lot of anger towards the non - magical world for allowing such a thing to happen.
There would be shock and disbelief. The wizarding world has always seen Hogwarts as a symbol of hope, knowledge and safety. If Harry destroys it, many would be in denial at first, thinking it couldn't be true. Wizards and witches from all over would come to the ruins, trying to figure out what had happened.
The wizarding world would be in shock. Harry is seen as a hero, and for him to kill Draco, even if Draco was from a 'less popular' side, would be a huge scandal. His friends like Hermione and Ron would be deeply conflicted. They would be torn between their loyalty to Harry and their disbelief at his actions.
The Ministry of Magic would probably be in an uproar. They might see Dumbledore's actions as a blatant abuse of power. They would send out Aurors to search for Harry and arrest Dumbledore. After all, Dumbledore is one of the most powerful wizards, and his actions would be seen as a threat to the stability of the wizarding world.